The present invention relates to a method for counting the number of articles or goods of the same kind using a weighing machine.
In processes of manufacturing articles it is often required to count quickly the number of articles or goods of the same kind. For this purpose such an indirect counting method has been widely used that instead of counting directly the articles one by one a total weight of the articles to be counted is first measured using a weighing machine and then the measured total weight is divided by a unit weight of the single article to obtain the number of the articles. However such a known method has inherently a disadvantage that if the goods have different weights, a counting error occurs theoretically. For instance, when a weight of a sample article is lighter or heavier than a mean weight of the articles to be counted by x%, a count value or figure calculated from the total weight of the articles includes an error of .+-.x%. Moreover in the actual weighing machine there is always a measuring error as well as a finite resolution and thus an actual error is always introduced other than the above mentioned theoretical error. For example, if the sample article of 1 gr is measured by using a weighing machine having an accuracy or resolution of 0.1 gr, there might be produced an error of 0.1 gr for 1 gr. That is the measured value includes an error of 10%. Thus when the number of articles is calculated with using such an erroneous unit weight, there might be produced a large error up to 10%. Such a large error is not acceptable in practice.
In order to avoid the theoretical and practical errors it has been proposed to adopt as a unit weight a mean weight of a number of sample articles such as thirty two or a hundred articles. But this method has also a disadvantage that many sample articles must be counted one by one manually and this does not meet an inherent object of a counting scale which can count the number of articles automatically or semi-automatically. Further a step of counting the number of many sample articles requires a lot of time, labour work and cencentration, which affects the practical use of the known counting scales.
As explained above in the known methods when the number of sample articles is small a large counting error is introduced, whilst when a large number of articles is used as samples, although a counting error can be decreased it is quite cumbersome to count such a large number of sample articles.